The epidemiology of cryptococcosis and the characterization of Cryptococcus neoformans isolated in a Brazilian University Hospital

Abstract

Cryptococcosis, a systemic disease caused by the fungus Cryptococcus neoformans/ Cryptococcus gattii is more severe in immunocompromised individuals. This study aimed to analyze the epidemiology of the disease, the molecular characteristics and the antifungal susceptibility of C. neoformans isolated from patients treated in a Brazilian university hospital. This retrospective study was conducted in the Clinical Hospital, Federal University of Uberlândia, and evaluated cases of cryptococcosis and strains of C. neoformans isolated from 2004 to 2013. We evaluated 41 patients, 85% of whom were diagnosed with AIDS. The fungus was isolated from the cerebrospinal fluid (CSF) of 21 patients (51%); 19.5% had fungemia and in 24% the agent was isolated from the CSF and blood, concurrently. Meningoencephalitis was the most frequent (75%) manifestation of infection. Despite adequate treatment, the mortality of the disease was 58.5%. Most isolates (97.5%) presented the VNI genotype (serotype A, var. grubii) and one isolate was genotyped as C. gattii (VGI); all the isolates were determined as mating type MATa and showed susceptibility to the tested antifungals (fluconazole, voriconazole, amphotericin B and 5-flucytosine). Although AIDS detection rates remain stable, opportunistic infections such as cryptococcosis remain as major causes of morbidity and mortality in these patients.

Figure 1. RFLP profiles (URA5 genes) from C. neoformans/C. gattii control strains. Columns 1 and 13: molecular markers (100 bp); columns 2 to 5: genotypes VNI, VNII, VNIII and VNIV, respectively; columns 6 to 9: genotypes VGI, VGII, VGIII and VGIV, respectively; column 10 is URA5 gene amplified product; columns 11 and 12 are clinical isolates Cryptococcus neoformans VNI and Cryptococcus gattii VGI, respectively.

Figure 2. RFLP profile of the URA5 genes from Cryptococcus sp obtained by double-digestion with HhaI and Sau96I. Column 1: Molecular maker (100 bp). Columns 2 to 7: isolated 2, 4, 5, 6, 7 and 8 (VNI), respectively; column 8: isolated 12 (VGI); Columns 9 to 13: isolates 13, 18, 22, 24 and 25 (VNI), respectively.